Parsing Binary Data

A lighting talk about parsing binary data in ruby with bindata gem.

Transcript

1. Parsing and Writing Binary Data in Ruby Jan Krutisch @halfbyte jan.krutisch@mindmatters.de
2. señor developer
4. Protracker "mod" files
5. Binary Format
7. ‣ Instrument Metadata ‣ Sample Data ‣ Pattern Data ‣ Sequence Data Mod File Contents
8. ‣ Instrument Metadata ‣ Sample Data ‣ Pattern Data ‣ Sequence Data Mod File Contents Array of Structs (=Array of Hashes)
9. ‣ Instrument Metadata ‣ Sample Data ‣ Pattern Data ‣ Sequence Data Mod File Contents Array of Structs (=Array of Hashes) Array of Blobs
10. ‣ Instrument Metadata ‣ Sample Data ‣ Pattern Data ‣ Sequence Data Mod File Contents Array of Structs (=Array of Hashes) Array of Blobs Arrays of Arrays of Arrays of Structs
11. ‣ Instrument Metadata ‣ Sample Data ‣ Pattern Data ‣ Sequence Data Mod File Contents Array of Structs (=Array of Hashes) Array of Blobs Arrays of Arrays of Arrays of Structs Array of Integers
12. Simple Approach
13. Serializer / Deserializer
14. Different Datatypes
15. Protracker Datatypes
16. Protracker Datatypes ‣ 8Bit signed binary blobs
17. Protracker Datatypes ‣ 8Bit signed binary blobs ‣ UInt8
18. Protracker Datatypes ‣ 8Bit signed binary blobs ‣ UInt8 ‣ UInt16 (Endianness?)
19. Protracker Datatypes ‣ 8Bit signed binary blobs ‣ UInt8 ‣ UInt16 (Endianness?) ‣ \0-Terminated/Padded Strings
20. Protracker Datatypes ‣ 8Bit signed binary blobs ‣ UInt8 ‣ UInt16 (Endianness?) ‣ \0-Terminated/Padded Strings ‣ Int4 (Yes, that‘s a signed halfbyte)
21. And this...
23. Procedural Mess
24. Declarative
25. gem "bindata"
26. class ProtrackerModule < BinData::Record endian :big string :name, :length => 20, :trim_padding => true array :samples, :type => Sample, :length => 31 uint8 :pattern_table_length uint8 :unused array :pattern_table, :type => :uint8, :initial_length => 128 [...]
27. class ProtrackerModule < BinData::Record endian :big string :name, :length => 20, :trim_padding => true array :samples, :type => Sample, :length => 31 uint8 :pattern_table_length uint8 :unused array :pattern_table, :type => :uint8, :initial_length => 128 [...]
28. class ProtrackerModule < BinData::Record endian :big string :name, :length => 20, :trim_padding => true array :samples, :type => Sample, :length => 31 uint8 :pattern_table_length uint8 :unused array :pattern_table, :type => :uint8, :initial_length => 128 [...]
29. class ProtrackerModule < BinData::Record endian :big string :name, :length => 20, :trim_padding => true array :samples, :type => Sample, :length => 31 uint8 :pattern_table_length uint8 :unused array :pattern_table, :type => :uint8, :initial_length => 128 [...]
30. class ProtrackerModule < BinData::Record endian :big string :name, :length => 20, :trim_padding => true array :samples, :type => Sample, :length => 31 uint8 :pattern_table_length uint8 :unused array :pattern_table, :type => :uint8, :initial_length => 128 [...]
31. array :patterns, :type => Pattern, :initial_length => lambda { pattern_table.max + 1 }
33. Demo
34. señor developer http://senordevelopershop.spreadshirt.de/ (europe) http://senordeveloper.spreadshirt.com/ (intl)